Secure your Password

You should run following script $ORACLE_HOME/rdbms/admin/utlpwdmg.sql
to secure your Password via Default Profile after DB creation. Or expect to see a lot of Policy Violations in your EM dbconsole for the instance.
I don't know why Oracle didn't make these setting 'Default' in the first place.
You could modify the CREATE FUNCTION verify_function part to fit your need.

alter profile default
limit failed_login_attempts 3
password_grace_time 10
password_life_time 45
password_lock_time unlimited
password_reuse_max 180
password_reuse_time unlimited password_verify_function VERIFY_FUNCTION;